Method and apparatus for high throughput multiple radio sectorized wireless cell

ABSTRACT

Methods and apparatus for high throughput wireless cells, capable of functioning as access points, are described. The wireless cells may be equipped with multiple radios to increase the amount of throughput available through a single wireless cell. Multiple antennas attached to the radios through RF switches may enable the wireless cell to service multiple clients simultaneously. The physical sectors of the antennas may overlapped to form virtual sectors that provide greater flexibility in client load management and in simultaneously servicing multiple clients. Attenuators may reduce interference from foreign wireless cells or clients. Systems and methods for assigning minimally interfering channels to either physical sectors or to radios to reduce interference between adjacent sectors and overlapping sectors are also disclosed. An antenna horn may also allow any antenna to be used as a directional antenna and may enable the antenna&#39;s angle of coverage to be adjusted. The use of multiple antennas on a client to reduce interferences is also described.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to, and the benefit of, U.S.provisional application Ser. No. 60/484,800 filed on Jul. 3, 2003 and toU.S. provisional application Ser. No. 60/493,663 filed on Aug. 8, 2003,both of which are hereby incorporated by reference in their entirety.

NOTICE OF MATERIAL SUBJECT TO COPYRIGHT PROTECTION

A portion of the material in this patent document is subject tocopyright protection under the copyright laws of the United States andof other countries. The owner of the copyright rights has no objectionto the facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the United States Patent andTrademark Office publicly available file or records, but otherwisereserves all copyright rights whatsoever. The copyright owner does nothereby waive any of its rights to have this patent document maintainedin secrecy, including without limitation its rights pursuant to 37C.F.R. § 1.14.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to wireless communications, and moreparticularly, to systems and methods for wireless cells, access points,and clients.

2. Description of Related Art

Many systems incorporate the IEEE 802.11 protocols, channels, andencoding to create wireless access points and clients capable ofcommunicating with each other regardless of the manufacturer of thedevice. As such, the popularity of wireless access and connectivity hasincreased demand for wireless throughput. However, the currentgeneration of wireless access points and devices are limited in thatthey use omni-directional antennas assigned to a single channel. Thedemand for wireless access has increased the demand for higher wirelessthroughput per wireless access point, the reduction of interferencebetween wireless cells, and the ability to use off-the-self componentsto deliver higher performance at lower cost.

BRIEF SUMMARY OF THE INVENTION

The invention overcomes the limitations and problems of the prior art byproviding an improved wireless cell that wirelessly communicates withother apparatus. In one embodiment, the enhanced antenna system includesat least one of sectorized coverage, attenuation, overlapping ornon-overlapping antenna physical sector arrangements, and minimallyinterfering radio channels to enable multiple antennas and multipleradios to substantially simultaneously operate in a single wireless celland to provide increased throughput, while minimizing the interferencewith foreign wireless systems.

In another embodiment, a horn may also enable any antenna type tofunction as a directional antenna and to provide either overlapping ornon-overlapping antenna physical sector arrangements, while at least oneof reducing interference from behind the antenna, interference betweenadjacent antennas, and multi-path interference. The invention may alsoinclude inexpensive, off-the-shelf radios with diversity switches toautomatically select between directional antennas used in an enhancedantenna system where the physical sectors of the two antennas connectedto a single radio may be oriented about 180 degrees opposed to eachother. The enhanced antenna system may also be used on apparatus thatfunction as clients to a wireless cell.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

A more complete understanding of the present invention may be derived byreferring to the detailed description and claims when considered inconnection with the Figures, wherein like reference numbers refer tosimilar elements throughout the Figures, and:

FIG. 1 is a diagram of an exemplary area of coverage of anomni-directional antenna.

FIG. 2 is a diagram of an exemplary area of coverage, or physicalsector, of a directional antenna.

FIG. 3 is a diagram of three exemplary adjacent physical sectors.

FIG. 4 is a diagram of two exemplary overlapping physical sectorsforming an exemplary virtual sector.

FIG. 5 is a diagram of two exemplary adjacent and one exemplaryoverlapping physical sectors forming two exemplary virtual sectors.

FIG. 6 is an exemplary diagram of optimal and absolute maximum coveragedistance and areas.

FIG. 7 is an exemplary diagram of the maximum transmit physical sectorsize when the radio is at maximum power.

FIG. 8 is a diagram of an exemplary physical sector size when the radiois at less than maximum power.

FIG. 9 is a diagram of an exemplary maximum receive physical sector sizewhen the attenuator provides no attenuation.

FIG. 10 is a diagram of an exemplary physical sector size when theattenuator attenuates.

FIG. 11 is a diagram of an exemplary maximum transmit physical sectoroverlaid on a non-maximum receive physical sector.

FIG. 12 is a diagram of three exemplary adjacent, non-overlappingphysical sectors providing about 360-degree coverage.

FIG. 13 is a diagram of three exemplary adjacent, non-overlappingphysical sectors providing about 360-degree coverage with orientationdifferent than physical sectors of FIG. 12.

FIG. 14 is a diagram of six exemplary overlapping physical sectorsforming six virtual sectors and providing about 360-degree coverage.

FIG. 15 is a diagram of three exemplary adjacent, non-overlappingphysical sectors.

FIG. 16 is a diagram of four exemplary adjacent, non-overlappingphysical sectors with orientation different than the physical sectors ofFIG. 15.

FIG. 17 is a diagram of seven exemplary overlapping physical sectorsforming six virtual sectors and providing about 180-degree coverage.

FIG. 18 is a diagram of an exemplary physical sector of a singledirectional antenna.

FIG. 19 is a diagram of two exemplary non-overlapping, non-adjacentphysical sectors.

FIG. 20 is a diagram of three exemplary physical sectors wherein twophysical sectors overlap and form a virtual sector.

FIG. 21 is a diagram of exemplary wireless cells, or access points, inindividual apartments.

FIG. 22 is a block diagram of an exemplary six antenna, three-radiowireless cell.

FIG. 23 is a block diagram of an exemplary six antenna, three-radiowireless cell with an attenuator in each radio receive path.

FIG. 24 is a block diagram of an exemplary six antenna, three-radiowireless cell with an attenuator in each antenna path.

FIG. 25 is a block diagram of an exemplary four antenna, two-radiowireless cell.

FIG. 26 is a block diagram of an exemplary four antenna, two-radiowireless cell with an attenuator in each radio receive path.

FIG. 27 is a block diagram of an exemplary four antenna, two-radiowireless cell with an attenuator in each antenna path.

FIG. 28 is a block diagram of an exemplary two-antenna, client enhancedantenna system.

FIG. 29 is a block diagram of an exemplary four-antenna, client enhancedantenna system.

FIG. 30 is a block diagram of an exemplary two-antenna, client enhancedantenna system with an attenuator in the radio receive path.

FIG. 31 is a block diagram of an exemplary four-antenna, client enhancedantenna system with an attenuator in the radio receive path.

FIG. 32 is a diagram of an exemplary coverage pattern for two,non-overlapping directional antennas providing about 360-degreecoverage.

FIG. 33 is a diagram of an exemplary coverage pattern of two,non-overlapping directional antennas providing about 360-degree coveragewith orientation different than the coverage pattern of FIG. 32.

FIG. 34 is a diagram of an exemplary coverage of four overlappingphysical sectors providing about 360-degree coverage and forming fourvirtual sectors.

FIG. 35 is a diagram of an exemplary horn.

FIG. 36 is a diagram of an exemplary antenna positioned in a horn toreduce angle of coverage.

FIG. 37 is a diagram of an exemplary antenna positioned in a horn toincrease angle of coverage.

FIG. 38 is a diagram of an exemplary omni-directional antenna positionedin a horn to provide directional coverage.

FIG. 39 is a diagram of an exemplary group of horns positioned toprovide about 360-degree overlapping or non-overlapping coverage.

FIG. 40 is a diagram of an exemplary channel assignment using threechannels for three, adjacent, non-overlapping physical sectors providingabout 360-degree coverage.

FIG. 41 is a diagram of an exemplary channel assignment using twochannels for six, adjacent, non-overlapping physical sectors providingabout 360-degree coverage.

FIG. 42 is a diagram of an exemplary channel assignment using threechannels for six, adjacent, non-overlapping physical sectors providingabout 360-degree coverage.

FIG. 43 is a diagram of an exemplary channel assignment using sixchannels for six, adjacent, non-overlapping physical sectors providingabout 360-degree coverage.

FIG. 44 is a diagram of an exemplary channel assignment using twochannels for four, adjacent, non-overlapping physical sectors providingabout 180-degree coverage.

FIG. 45 is a diagram of an exemplary channel assignment using threechannels for four, adjacent, non-overlapping physical sectors providingabout 180-degree coverage.

FIG. 46 is a diagram of an exemplary channel assignment using fourchannels for four, adjacent, non-overlapping physical sectors providingabout 180-degree coverage.

FIG. 47 is a diagram of an exemplary channel assignment using twochannels for three, adjacent, non-overlapping physical sectors.

FIG. 48 is a diagram of an exemplary channel assignment using threechannels for three, adjacent, non-overlapping physical sectors.

FIG. 49 is a diagram of an exemplary channel assignment using onechannel for two, non-adjacent, non-overlapping physical sectors.

FIG. 50 is a diagram of an exemplary channel assignment using onechannel for one physical sector.

FIG. 51 is a diagram of an exemplary wireless cell formed using three,adjacent, non-overlapping physical sectors providing about 360-degreecoverage and having a channel assigned to each physical sector.

FIG. 52 is a diagram of an exemplary wireless cell formed using three,adjacent, non-overlapping physical sectors providing about 360-degreecoverage with orientation different than the wireless cell shown in FIG.51 and having a channel assigned to each physical sector.

FIG. 53 is a diagram of an exemplary wireless cell formed using sixoverlapping physical sectors that form six virtual sectors and providesabout 360-degree coverage.

FIG. 54 is a diagram of an exemplary wireless cell formed using four,adjacent, non-overlapping physical sectors providing about 180-degreecoverage and having a channel assigned to each physical sector.

FIG. 55 is a diagram of an exemplary wireless cell formed using three,adjacent, non-overlapping physical sectors providing about 180-degreecoverage with orientation different than the wireless cell shown in FIG.54 and having a channel assigned to each physical sector.

FIG. 56 is a diagram of an exemplary wireless cell formed using sevenoverlapping physical sectors that form six virtual sectors.

FIG. 57 is a diagram of an exemplary wireless cell with fournon-overlapping physical sectors providing about 180-degree coverage andservicing clients.

FIG. 58 is a diagram of an exemplary wireless cell with six overlappingphysical sectors providing about 360-degree coverage and servicingclients.

FIG. 59 is a diagram of an exemplary client using a two-antenna, clientenhanced antenna system placed in an environment of three foreignwireless cells.

FIG. 60 is a diagram of an exemplary client using a four-antenna, clientenhanced antenna system placed in an environment of three foreignwireless cells.

FIG. 61 is a flow chart of a method for performing an exemplary activescan.

FIG. 62 is a flow chart of a method for performing an exemplary power oninitialization.

FIG. 63 is a flow chart of a method for performing an exemplarybackground loop.

FIG. 64 is a flow chart of an exemplary method for a client to informthe wireless cell that the throughput of the assigned channel isinsufficient.

FIG. 65 is a flow chart of an exemplary method for advising the wirelesscell that the channel change was successful.

FIG. 66 is a flow chart of an exemplary method for advising the wirelesscell that the new channel does not provide sufficient throughput.

FIG. 67 is a flow chart of an exemplary method for advising the wirelesscell that a channel change has impaired performance.

FIG. 68 is a flow chart of an exemplary method for the wireless cell toadvise the client that no channel may provide sufficient throughput.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The detailed description of exemplary embodiments of the inventionherein makes reference to the accompanying drawings, which show theexemplary embodiment by way of illustration and its best mode. Whilethese exemplary embodiments are described in sufficient detail to enablethose skilled in the art to practice the invention, it should beunderstood that other embodiments may be realized and that logical andmechanical changes may be made without departing from the spirit andscope of the invention. Thus, the detailed description herein ispresented for purposes of illustration only and not of limitation. Forexample, the steps recited in any of the method or process descriptionsmay be executed in any order and are not limited to the order presented.

For the sake of brevity, conventional data networking, applicationdevelopment and other functional aspects of the systems (and componentsof the individual operating components of the systems) may not bedescribed in detail herein. Furthermore, the connecting lines shown inthe various figures contained herein are intended to represent exemplaryfunctional relationships and/or physical couplings between the variouselements. It should be noted that many alternative or additionalfunctional relationships or physical connections may be present in apractical system.

As will be appreciated by one of ordinary skill in the art, the presentinvention may be embodied as a customization of an existing system, anadd-on product, upgraded software, a stand alone system, a distributedsystem, a method, a data processing system, a device for dataprocessing, and/or a computer program product. Accordingly, the presentinvention may take the form of an entirely software embodiment, anentirely hardware embodiment, or an embodiment combining aspects of bothsoftware and hardware. Furthermore, the present invention may take theform of a computer program product on a computer-readable storage mediumhaving computer-readable program code means embodied in the storagemedium. Any suitable computer-readable storage medium may be utilized,including hard disks, CD-ROM, optical storage devices, magnetic storagedevices, and/or the like.

An omni-directional antenna 10 sends and receives radio signals insubstantially all directions. The ideal area of coverage 12, ignoringany null areas, of the omni-directional antenna 10 in FIG. 1 issubstantially circular because it is shown on paper in two dimensions,but in reality, the ideal area of coverage of an omni-directionalantenna is similar to a sphere. The ideal area of coverage 16, ignoringany back-lobes, of the directional antenna 14 in FIG. 2 is shown in twodimensions as a part of a circle; however, in reality, the ideal area ofcoverage of a directional antenna is an angular fraction of a sphere.The arc 18 indicates the angle of coverage of directional antenna 14 andarea of coverage 16. The angle of coverage of a directional antennaranges from a fraction more than 0 degrees to a fraction less than about360 degrees. The operational center of directional antenna 14 is thecenter of its angular area of coverage. For example, the angle ofcoverage of antenna 14 is about 20 degrees, but its operational centeris at about 10 degrees.

The line depicting the antenna area of coverage does not necessarilyindicate the maximum range of the radio attached to the antenna. Forexample, the circle labeled 12 in FIG. 1 does not necessarily mean thatthe radio attached to omni-directional antenna 10 cannot transmitfarther than area of coverage 12. Circle 12 may depict the absolutetransmission or reception limit, but it may also represent the distanceat which most radio signals decrease to a predetermined signal strengthwhile the maximum limits may extend beyond circle 12. The same conceptapplies to the area of coverage of a directional antenna; however, theangle of coverage 18 may not change appreciably. For example, thedistance 328 from directional antenna 14 in FIG. 6 to the outer edge ofarea of coverage 330 represents the absolute maximum distance that asignal of detectable strength may be transmitted or received by theradio attached to antenna 14. The distance 326 and the dash area ofcoverage 324 represent the extent of usable signal strength coverage forreliable transmission. A client position inside area of coverage 324,without considering environmental anomalies, may receive the minimumusable radio signal strength. A client outside area of coverage 324, butinside area of coverage 330 may still be detected by antenna 14, but theclient may receive signals with less than usable signal strength. Notethat the angle of coverage does not change appreciably between optimalarea of coverage 324 and absolute maximum area of coverage 330 becausedirectional antennas attenuate signals at the edge of their angle ofcoverage.

In this application, any area of coverage drawn does not necessarilyrepresent the maximum limits of transmission and reception 330, butrather, the area represents the usable signal level area of coverage324. Therefore, two adjacent areas of coverage may interfere with eachother to some extent even though their drawn areas of coverage are notshown to overlap. Referring to FIG. 21, the drawn areas of coverage ofthe directional antennas of room 112 do not overlap with the areas ofcoverage of the directional antennas of rooms 106 or 114; however, ifthe maximum extent of all the antennas were shown, they may interferewith each other.

The area of coverage 16 of directional antenna 14, shown in FIG. 2, isalso referred to as a physical sector. Three adjacent physical sectors,16, 22, and 28, of antennas 14, 20, and 26 are shown in FIG. 3. Becauseantennas 14, 20, and 26 are directional, the radio signals along theircontiguous side may be attenuated. Therefore, adjacent physical sectorsthat use the same radio channel (frequency) may interfere with eachother, but the amount of interference may be controlled, in oneembodiment, through selecting directional antennas with high attenuationat the edges of their physical sector, by placing the directionalantennas with extra angular spacing between them, or by using a horn asdescribed below. Even though there is some interference between physicalsectors 16 and 22, and 22 and 28, they are considered to be adjacent andnon-overlapping because they are positioned so their angle of coveragedoes not overlap. For example, assume that each antenna 14, 20, and 26has an angle of coverage of 20 degrees. If antennas 14, 20, and 26 arepositioned so that their combined angle of coverage is 60 degrees (i.e.,20 degrees each), then they do not overlap.

If antennas are placed so that their combined angle of coverage is lessthan the sum of their individual angle of coverage, as shown in FIG. 4,then the physical sectors overlap. The area of overlap of physicalsectors 16 and 22 in FIG. 4 may be referred to as a virtual sector 24.The size of virtual sector 24 is the amount of overlap between physicalsectors 16 and 22. Virtual sectors may range in size from a smallfraction of a physical sector to the entire sector if the physicalsectors completely overlap. Overlapping physical sectors do not need tobe of similar size and the amount of overlap is not fixed. The physicalsectors 16, 22, and 28 in FIG. 5 are all similar in size. Physicalsector 16 overlaps half of physical sector 22 and forms virtual sector30, which is about half the size of either physical sector 16 or 22.Physical sectors 22 and 28 also overlap by about half their angularwidth and form virtual sector 32. In other words, physical sector 22overlaps 50% each of adjacent physical sectors 16 and 28. The area ofcoverage within a virtual sector may receive antenna, and thereforeradio, coverage from more than one source. Virtual sectors 24 or 30 mayreceive coverage from antennas 14 and 20. Virtual sector 32 may receivecoverage from antennas 20 and 26. If antennas 14 and 20 are attached todifferent radios, then the virtual sectors are serviced by two radiosinstead of the single radio that services either physical sector. Thereare no limits to how many physical sectors may overlap, which means thatmultiple antennas and multiple radios may service a virtual sector. Theadvantage of overlapping sectors will become apparent when enhancedantenna systems and wireless cells using enhanced antenna systems aredescribed below.

Antennas may be connected to radios such that the radio may communicatewith other apparatus. Depending on the protocol, most radios transmitand receive information through a channel or set of channels that may beassociated in some way to radio frequencies. Two apparatus typically usethe same channel in order to communicate. Communication occurs when twoapparatus use the same channel to transmit to each other or receive fromeach other. If two apparatus simultaneously transmit on the samechannel, the transmissions may interfere with each other and may be madeunintelligible. Depending on the frequency of the channels and theapparatus configuration, two apparatus set to different channels mayinterfere with each other. However, some channels interfere onlyminimally with each other when transmitting in the same areasimultaneously. Two radios using different, minimally interferingchannels interfere with each other only minimally when simultaneouslytransmitting.

The 802.11 protocols provide minimally interfering channels that allowradios using different channels to operate simultaneously in the samephysical area. Minimally interfering channels are advantageous whenusing overlapping or adjacent physical sectors. As discussed above,physical sectors 16 and 22 in FIG. 3 interfere with each other to someextent when they use the same channel because they are adjacent.Overlapping physical sectors, as shown in FIG. 4 and FIG. 5, mayinterfere with each other even more than adjacent physical sectors ifeach physical sector were assigned the same channel. However, the radiosdo not interfere with each other even though the physical sectors areadjacent or overlapping, if the radios attached to the antennas ofadjacent or overlapping physical sectors use different minimallyinterfering channels. The assignment of channels to overlapping andadjacent physical sectors plays an important role in enabling multipleradios to operate simultaneously in the same or nearby physical space.

For a given wireless cell, the area of coverage of an antenna and itsassociated radio (i.e., the size of the physical sector), is often tiedto the power of its transmit signal and its sensitivity when receivingsignals. An antenna, with its attached radio, has a greater area ofcoverage, and thereby a larger physical sector, if it transmits strongsignals and detects weak signals. The radio, for the most part, maycontrol the strength of the transmitted signal. Adjusting the transmitpower of an off-the-self radio changes the area of coverage, or size, ofthe antenna's physical sector. The physical sector 34 and distance 36shown in FIG. 7 represents the size of the physical sector when theradio transmits at maximum power. As radio transmission power decreases,physical sector size 38 and distance 40, as shown in FIG. 8, alsodecrease.

The same variation in size occurs for receive signals if an attenuatoris placed in the radio receive path. An attenuator with zero attenuationallows the maximum receive physical sector 42 and receive distance 44 asshown in FIG. 9. As the attenuation increases, the size of the receivephysical sector 46 and receive distance 48 decrease as shown in FIG. 10.Clearly, the size of the transmit physical sector may also be adjustedby using an attenuator in the transmit path. In other embodiments, thesize of the receive sector may be adjusted using variable gain. Bothtransmit and receive physical sector sizes may be simultaneouslyadjusted if an attenuator is placed between the radio and the antennathereby affecting both the transmit and receive paths substantiallyequally. Obviously, the size of the transmit and receive physicalsectors may be adjusted independently. FIG. 11 shows a maximum transmitphysical sector 34 and a non-maximum receive physical sector 46. Theutility of independently adjustable transmit and receive physical sectorsizes becomes apparent when methods of dealing with noisy foreignclients are discussed; however, decreasing the size of the receivephysical sector reduces the interference of noisy and unwanted sources.One of the main strategies is to reduce the size of the receive physicalsector to the point that unwanted noise is reduced without cutting offcommunication with desirable clients, while at the same timetransmitting a strong signal to all clients within the transmit physicalsector. Attenuation may also be adjusted to provide optimal datathroughput between a wireless cell and a client.

A wireless cell includes, for example, a collection of antennas, radios,and potentially other devices (e.g., attenuators, RF switches, etc.)under the common control of a processor or multiple processors. Anexemplary wireless cell communicates with other wireless cells, wirelessclients, or other wireless devices. One embodiment of a wireless cell isan access point, which combines wireless communication with an I/O portconnected to a wired network thereby allowing communication betweenwired and wireless devices. For a given wireless cell, the cell'scoverage, meaning the physical area serviced wirelessly, depends on thenumber, type, physical sector size, and arrangement of the antennas. Thecoverage of a wireless cell that uses an omni-directional antenna isideally a sphere type shape as shown in two dimensions in FIG. 1.Directional antennas provide greater flexibility in providing wirelesscell coverage.

The physical sectors from three, 120-degree, directional antennascombine to provide about 360-degree, non-overlapping wireless cellcoverage as shown in FIG. 12 or FIG. 13. Note that the orientation ofthe antennas in FIG. 12 vary from the antennas of FIG. 13 by about 60degrees. If the antennas from FIG. 12 were combined with the antennas ofFIG. 13 into the same wireless cell while preserving their orientation,the wireless cell may have the coverage shown in FIG. 14. The wirelesscell coverage of FIG. 14 has six overlapping physical sectors: 56, 58,60, 62, 64, and 66. Each physical sector is similar size and overlapsabout half of two adjacent physical sectors. For example, physicalsector 60 overlaps about half of physical sector 66 and about half ofphysical sector 64. The overlap of sector 60, 64, and 66 form virtualsector 76 and 74. Each physical sector overlaps two adjacent,non-overlapping physical sectors to form six virtual sectors: 68, 70,72, 74, 76, and 78. Each virtual sector includes about 60-degree angleof coverage.

FIG. 14 shows physical sectors of substantially equal size, but, asmentioned earlier, the physical sectors are not limited to havingsubstantially equal angle of coverage, nor do they need to be ofsubstantially equal transmit or receive size. Additionally, in FIG. 14,each virtual sector is formed by the overlap of two physical sectors,but the number of physical sectors that overlap to form a virtual sectoris not limited. Wireless cell coverage depends on the characteristics ofthe individual physical sectors and how they combine. There are norequirements or limitations on size or method of combination; however,when providing about 360-degree wireless cell coverage, one embodimentincludes physical sectors of substantially equal sizes thatsubstantially equally overlap two non-overlapping and adjacent sectors.Wireless cell coverage does not need to be only 360 degrees.

The three, non-overlapping, adjacent, physical sectors of FIG. 15provide wireless cell coverage that is less than about 180 degrees. Fournon-overlapping, adjacent, physical sectors shown in FIG. 16 provideabout 180-degree wireless cell coverage. The combination of the wirelesscell coverage from FIG. 15 and FIG. 16 form the wireless cell coverageshown in FIG. 17. Note that physical sector 80 overlaps physical sectors86 and 88 thereby forming two virtual sectors and physical sector 84overlaps physical sectors 90 and 92 thereby also forming two virtualsectors. However, in the areas marked 94 and 96, there are no physicalsector overlaps; therefore, they are not virtual sectors and havecoverage by the single antennas 86 and 92, respectively. It may bepossible to extend the angle of coverage of antenna 80 to overlap all ofphysical sector 86, thereby creating a virtual sector in almost all ofphysical sector 86 covered by physical sectors 80 and 86. The same maybe done with physical sector 84 with respect to physical sector 92.

FIG. 18 shows an exemplary coverage of a wireless cell based on a singledirectional antenna. The wireless cell coverage shown in FIG. 19 isformed by two, non-adjacent physical sectors of different sizes. Thecombination of the wireless cell areas of coverage of FIG. 18 and FIG.19 into a single wireless cell results in the wireless cell coverageshown in FIG. 20. The overlap of physical sector 98 and 100 form virtualsector 104. As stated above, no requirements or limitations exist, butwireless cell coverage may depend on, for example, the number, type,physical sector size, and arrangement of the antennas forming thewireless cell.

Wireless cells may include related and unrelated (i.e., foreign)wireless cells. Wireless cells may be related if they have some level ofcommon control. Generally, related wireless cells form a wirelessnetwork capable of, for example, routing between wireless cells,collectively assigning channels to avoid interference, and automaticphysical sector size adjustment. Foreign wireless cells are independentwireless cells with no central method of control or method ofpeer-to-peer control. For example, imagine each rectangular box in FIG.21 to be an apartment in a building. Apartments 106, 110, 112, 114, and116 have each set up wireless cells. The wireless cells in differentapartments are not related. They are foreign to each other. Nosubstantial set up or control communications takes place between thewireless cells in different apartments and no common processorcoordinates them. The wireless cells do not collectively decide whichchannel should be assigned to each physical sector to minimizeinterference between apartments. If a wireless cell in one apartmentassigns channels that interfere with a wireless cell in anotherapartment, the wireless cells do not coordinate between themselves toreduce interference because they are foreign to each other.

An antenna-sharing device (ASD) enables two different radio signalsources to share the same antenna. The ASD 148 shown in FIG. 23 combinesthe transmit path 160 from radio 136 with the receive path 162 into atransmit/receive path connected to RF switch 130.

A client may be any type of wireless apparatus that communicates orcooperates with a wireless cell. A client may be distinguished from awireless cell in that a client generally communicates only with a singlewireless cell whereas a wireless cell communicates with many clients.However, the definition should not be limiting because one wireless cellmay appear to be a client to another wireless cell. Another definitionof a client is that a client either produces or consumes data, whereaswireless cells generally only transfer data between wired or wirelesssources. Some information is produced and consumed by wireless cells,but usually the information is related to the control of communicationsbetween wireless cells, or between wireless cells and clients. In an802.11 wireless system, a client is a device that associates with anduses the network services of access points.

No limitations are assumed for the clients disclosed in thisapplication. Clients may have one or more radios and one or moreantennas. A client may function as a slave to a wireless cell or theclient may work in conjunction with the wireless cell by transmittingcontrol information and requests to the wireless cell in addition todata. Control information from a client may include, for example, signalquality, desired antenna, error rate, number of dropped frames, desiredthroughput, throughput delivered, wireless cells detected, and/or anyother conceivable information. Client requests may include, for example,retransmission, channel change, throughput demands, authentication,variation in transmit power, and/or a request to modify anycommunication factor.

Clients are not limited to communicating only with wireless cells. Inthe ad hoc mode, clients may communicate directly with each otherwithout the central coordination of a wireless cell. The advancedclients described in this application are not limited to communicatingwith wireless cells. Advanced clients are also capable of operating inthe ad hoc mode.

Advanced clients may communicate control information to a wireless cell.All clients may associate with a wireless cell and may send data to andreceive data from a wireless cell, but advanced clients may send thewireless cell information that helps the wireless cell manage itscommunication with the clients it serves. An advanced client may informthe wireless cell, for example, of its desired throughput, bufferfullness, signal quality, and/or other relevant information.

Wireless cells, access points, clients, or other devices thatcommunicate using antennas may use an enhanced antenna system. Anenhanced antenna system may use, for example, an antenna physical sectorarrangement, switching, and attenuation to increase receive sensitivity,reduce the effects of noise, provide improved coverage, provideincreased transmission range, and/or to allow higher antenna density ascompared to a simple antenna. An enhanced antenna system may, forexample, combine antennas with other apparatus, use antenna positioning,shielding, channel assignment, intermittent use, noise sampling,operational protocols, and/or a combination of techniques to improveperformance.

An enhanced antenna system may include one or more antennas of varioustypes such as, for example, omni-directional, directional, patch,parabolic, beam, yagi, MIMO, antenna arrays, adaptive antenna arrays, orsimilar devices. In one embodiment, an antenna for an enhanced antennasystem may be a directional antenna with about 5 to 8 dB attenuation insignal strength from the operation center to the edge of the physicalsector and at least about 15 dB signal rejection from behind theantenna. The attenuation from operation center to physical sector edgemay range from about 3 dB to 20 dB. The amount of attenuation from theoperation center to the physical sector edge and the signal rejectionfrom behind the antenna may be modified by use of a horn (as describedbelow) or similar reflective element such as a parabolic reflector, afour-corner reflector, or any reflector capable of producing a desiredarea of coverage. A horn, or a reflective element, also allowsomni-directional and other types of antennas to be adapted to providedesired characteristics and angle of coverage. The desired antenna maybe used with or without the horn.

A Multiple Input Multiple Output (MIMO) antenna is not a single antenna,but many antennas. In this invention, a MIMO antenna array may be usedas any other single antenna type may be used. Just as a single antennaservices a physical sector of a certain angle and area of coverage, aMIMO antenna array may provide a desired angle and area of coverage. Forexample, if four 90-degree, directional antennas provide about 360degrees of non-overlapping coverage, each directional antenna may bereplaced by a MIMO antenna array to provide similar coverage. The MIMOantenna may be used in both wireless cells and clients. MIMO antennasmay use any combination of spatial, polarization, or angle antennadiversity. The MIMO antenna array may be fixed or adaptive for eithertransmit, receive, or both. When receiving, the MIMO antenna may use,for example, a maximum ratio combiner, an optimal linear combiner,selection diversity, or any combination of these methods or othermethods for combining the signals from multiple antennas into a singlesignal. When transmitting, the MIMO antenna may use any type of encodingincluding, for example, OFDM, space-time-codes, or weighting of theantenna signals in the array to accomplish beam steering. Duringtransmission or reception, all or any subset of antennas in the MIMOarray may be used or selection diversity may be used to limit the numberof antennas used. Antenna diversity may be used in the transmit path, inthe receive path, or in both transmit and receive paths. The signal fromeach antenna, transmitted or received, may or may not be weighted.

Servicing a physical sector with a MIMO antenna means that all antennasin the MIMO array use the channel (discussed below) assigned to thephysical sector. Signal attenuation may be added after each antenna,after the signal combiner, or in the signal processor that manipulatesthe incoming signals.

Although MIMO antennas are arrays of antennas, any antenna array may beused as a single antenna or a MIMO antenna may be used. For example, adirectional antenna with about 120-degree angle of coverage may bereplaced by an antenna array that provides similar coverage. The arraymay be fixed or adaptive. Adaptive arrays may use adaptive array weightsto transmit directional beams within the angle and area of coverage tosend a stronger signal to a desired client. During reception, anadaptive array may use array weights to direct a beam substantiallytowards the transmitting client and substantially null out any sourcesof interference.

An exemplary embodiment of an enhanced antenna system uses multipledirectional antennas arranged with overlapping physical sectors combinedwith attenuators only in the receive path. Six exemplary embodiments ofenhanced antenna systems are discussed below; however, one skilled inthe art will appreciate that enhanced antenna systems are not limited tothe embodiments described.

A first embodiment of an enhanced antenna system uses multipledirectional antennas arranged such that the antenna's physical sectorsare adjacent, but non-overlapping. During communication, only oneantenna is active at a time. The antenna used to communicate is selectedby measuring the signal strength of the desired receive signal througheach antenna. The antenna that detects the strongest receive signal isused and the other antennas are either disabled or ignored. The firstembodiment of an enhanced antenna system provides increased performanceby using the antenna that provides the best reception. One potential useof the first embodiment of an enhanced antenna system is with a clientthat exclusively uses the antenna that provides the best receive signalfrom the wireless cell. Attenuation, as shown in the receive path inFIG. 30 and FIG. 31, is used to further decrease interference fromunwanted signals.

Non-overlapping, adjacent antenna arrangements suitable for the enhancedantenna system first embodiment are shown in FIG. 12, FIG. 13, FIG. 15,FIG. 16, and FIG. 18. Hardware capable of supporting the firstembodiment of an enhanced antenna system is shown in FIG. 28 throughFIG. 31. Clearly, the coverage patterns of FIG. 12, FIG. 13, and FIG. 15include three directional antennas. The hardware of FIG. 29 or FIG. 31may provide the coverage pattern shown in FIG. 16. The antennas are notrequired to have substantially equal angle of coverage or physicalsector size; however, four directional antennas with about 45-degreeangle of coverage may produce the coverage pattern shown in FIG. 16. Anyof the antennas 232, 234, 236, or 238 may be assigned to physicalsectors 86, 88, 90, or 92. One possible assignment is to assign antenna232, 234, 236, and 238 to physical sectors 86, 88, 90, and 92respectively.

Other potential variations on the enhanced antenna system firstembodiment may include using the antenna that receives the strongestreceive signal exclusively for reception and the antenna that transmitsthe strongest transmit signal exclusively for transmission withoutrequiring the transmit and receive antennas to be the same. The antennasmay also be arranged to be non-overlapping, but also non-adjacent.

A second embodiment of an enhanced antenna system uses multipledirectional antennas arranged such that the antenna physical sectorsoverlap. Unlike the first embodiment of an enhanced antenna system,multiple antennas in the second embodiment may be simultaneously active,which may increase the desirability of the second embodiment for awireless cell. Exemplary patterns for overlapping physical sectors areshown in FIG. 4, FIG. 5, FIG. 14, FIG. 17, and FIG. 20. The exemplaryantennas and hardware shown in FIG. 22, FIG. 25, FIG. 28, or FIG. 29 maybe adapted to provide overlapping coverage and to implement the secondembodiment of an enhanced antenna system. The coverage of two antennasin each virtual sector may allow the second embodiment of an enhancedantenna system to use the best antenna of two antennas to communicatewith a device in the virtual sector. Although the second embodiment ofan enhanced antenna system uses two antennas per virtual sector, thereis essentially no limitation on the number of antennas per virtualsector. In one embodiment, each physical sector may be of similar sizeand the physical sectors may overlap two adjacent physical sectors byabout 50% thereby forming virtual sectors with angle of coverage of halfof the physical sector angle of coverage.

Producing the coverage pattern of FIG. 14 may include six antennas withangular physical sectors of about 120 degrees. The hardware of FIG. 22may be adapted to provide the coverage shown in FIG. 14 by setting thephysical sectors of antennas 118 through 128 to substantially correspondto physical sectors 56 through 64. However, the exemplary antennaarrangement may include the operational centers of the two antennasattached to any single radio (136, 138, or 140) by way of an RF switch(130, 132, or 134) point in substantially opposite directions.Off-the-shelf radios may include built-in RF switches, known asdiversity switches, and since a radio uses a single channel, assigningantennas attached to the same RF switch (diversity switch) to facesubstantially opposite directions enables the physical sectors tosubstantially conform to exemplary channel assignment techniquesdisclosed below. The operational center of physical sector 56 points inthe substantially opposite direction of physical sector 64. Physicalsectors 58 and 66, and 60 and 62 also point in substantially oppositedirections. One exemplary antenna assignment is to assign the physicalsectors of antennas 118, 120, 122, 124, 126, and 128 to substantiallycorrespond to 56, 64, 58, 66, 60, and 62 respectively. Although channelassignments have not yet been described, the exemplary channelassignment for a three-channel system is shown in FIG. 53. Assigningantennas attached to the same radio to face substantially oppositedirections minimizes the likelihood that adjacent physical sectors donot use the same channel.

The exemplary hardware of FIG. 25 may be adapted to provide the coverageshown in FIG. 34. Using the exemplary antenna physical sector assignmentfor off-the-shelf radios described above, the physical sectors ofantennas about 180 and 182 may substantially correspond to physicalsectors 250 and 252 in FIG. 32, and the physical sectors of antennas 184and 186 may substantially correspond to physical sectors 254 and 256 ofFIG. 33. Overlapping the coverage of FIG. 32 and FIG. 33 produces thepattern shown in FIG. 34. The angle of coverage of each antenna may beabout 180 degrees. Other physical sector arrangements may also meet theopposing sector preference.

Wireless coverage patterns like that shown in FIG. 17 may not meet anexemplary physical sector assignment for an off-the-shelf radiodescribed above because no physical sectors point in substantiallyopposite directions. In such circumstances, antennas may be attached tothe common radio through an RF switch and arranged such that theirphysical sectors are not adjacent or overlapping. Possible arrangementsbecome apparent when channel assignment is incorporated as describedbelow.

The hardware shown in FIG. 29 does not represent a currentoff-the-shelf-radio because the radio through an RF switch attaches tomore than two antennas. However, the antenna physical sectors may bearranged to provide the overlapping wireless cell coverage pattern ofFIG. 34, thereby meeting the enhanced antenna system second embodimentfeature of overlapping sectors.

Another possible antenna physical sector arrangement includes physicalsectors which overlap by about 100% thereby forming virtual sectorssubstantially equal in size to a physical sector. An example of such ascheme may exist where at least two antenna physical sectors areassigned to position 62 in FIG. 13, at least two additional antennaphysical sectors are assigned to position 64, and at least an additionaltwo antennas to position 66. The physical sectors of the antennas ineach position 62, 64, or 66 may completely overlap and form virtualsectors the size of the individual antenna physical sector. Although anexemplary hardware to support such arrangements is not described in thisapplication, the arrangement is mentioned to emphasize that the enhancedantenna system embodiments disclosed are not limitations, but specificexamples of possible approaches.

A third embodiment of an enhanced antenna system is similar to thesecond embodiment in that it uses multiple directional antennas arrangedsuch that the antenna physical sectors overlap; however, the thirdembodiment may be different in that, for example, an attenuator isplaced between each antenna and its corresponding RF switch as shown inFIG. 24 and FIG. 27. The third embodiment has the advantage of virtualsectors covered by multiple antennas, along with the ability toattenuate the effects of unwanted receive signals with the attenuators.The level of attenuation may be changed between transmission andreception; thereby, allowing the wireless cell to attenuate unwantedreceive signals while still transmitting at substantially full strength.The attenuator and methods of attenuation are described in more detailbelow. The arrangement of the antenna physical sectors of the enhancedantenna system third embodiment may be similar to the overlappingarrangements described in the second embodiment.

The fourth embodiment of an enhanced antenna system is the exemplaryembodiment. Like the third embodiment, the fourth enhanced antennasystem embodiment uses multiple directional antennas arranged such thatthe antenna physical sectors overlap. The fourth embodiment alsoincludes attenuators, but the attenuators of the fourth embodiment areplaced only in the receive path as shown in FIG. 23, FIG. 26, FIG. 30and FIG. 31. Placing the attenuator only in the receive path, unlike thethird embodiment, minimizes the effect of the transmit signals by theattenuator. The fourth embodiment includes virtual sectors covered bymultiple antennas, and the ability to attenuate the effects of unwantedreceive signals using the attenuators without affecting the transmitsignal. The fourth embodiment may use the attenuators to decrease thereceive noise floor while at the same time providing a strong transmitsignal.

Current off-the-shelf radios do not provide an attenuator in the receivepath; however, attenuation of only the receive signal may beaccomplished by other methods. Attenuation is more fully discussedbelow. Arranging antenna physical sectors in substantially opposingpositions may still be desired where the radio connects through an RFswitch to two antennas.

The fifth embodiment of an enhanced antenna system is similar to thethird embodiment in that it includes attenuators placed between eachantenna and its corresponding RF switch as shown in FIG. 24 and FIG. 27;however, the fifth embodiment may not use overlapping physical sectors.Although the fifth embodiment may not include virtual sectors, the fifthembodiment provides multiple sectors and the ability to attenuateunwanted receive signals. The fifth embodiment is similar to the thirdembodiment where the transmit signal may be attenuated by theattenuator; however, transmit and receive operations may use differentattenuation values.

An exemplary arrangement of antenna physical sectors may be adjacent asshown in FIG. 12, FIG. 13, FIG. 15, FIG. 16, FIG. 32, and FIG. 33;however, adjacent physical sectors is not a requirement. The physicalsector arrangement of FIG. 19 is possible, or an arrangement where somephysical sectors are adjacent, but not other sectors. The physicalsectors are not required to have the same angle of coverage or physicalsector size. The wireless cell coverage may range from narrow up toabout 360 degrees.

The hardware shown in FIG. 24 may support the physical sector patternshown in FIG. 42. As described in the second embodiment, an exemplaryantenna physical sector assignment may include the antennas that areattached to the same radio point in the substantially oppositedirection. An exemplary assignment may be met by assigning antenna 118,120, 122, 124, 126, and 128 to substantially correspond to position 276,282, 278, 284, 280, and 286, respectively, as depicted in FIG. 42. Otherassignments that meet the preference are possible.

The hardware shown in FIG. 27 may support the physical sector patternshown in FIG. 16. As described in the second embodiment, if the physicalsectors of the wireless cell coverage do not face in substantiallyopposite directions, an exemplary antenna physical sector placement mayarrange physical sectors of antennas connected to the same radio so theyare not adjacent. An exemplary arrangement may be met by assigning thephysical sectors of antennas about 180, 182, 184, and 186 to positions86, 90, 88, and 92, respectively. Other assignments that meet thepreference are also possible. It is also possible to arrange thephysical sectors attached to the same radio to adjacent locations amongother suitable arrangements.

The sixth embodiment of an enhanced antenna system is similar to thefifth embodiment in that the physical sectors are non-overlapping, butit is also like the fourth enhanced antenna system embodiment because ithas attenuators in the receive path. While the sixth embodiment may nothave virtual sectors, it may attenuate unwanted receive signals withoutsubstantially affecting transmit signal strength.

The considerations for antenna physical sector arrangement are similarto those of the fifth embodiment. The hardware shown in FIG. 23, FIG.26, FIG. 30, and FIG. 31 may support the physical sector patterns shownin FIG. 42, FIG. 16, FIG. 19, and FIG. 16, respectively. As mentioned inthe fourth enhanced antenna system embodiment, current off-the-shelfradios may not provide an attenuator in the receive path; however,physical sector assignment for the sixth enhanced antenna systemembodiment may be similar to the approach used in the fourth enhancedantenna system embodiment.

In certain enhanced antenna system embodiments, attenuators may decreaseinterference from unwanted signals. Attenuating the incoming signaldecreases the level of the desired signal and the undesirable noisethereby improving the desired signal's signal-to-noise ratio.Attenuation may improve the signal-to-noise ratio even when the radiouses automatic gain control (AGC) to try to acquire weaker incomingsignals. The exemplary attenuators in FIG. 23, FIG. 24, FIG. 26, FIG.27, FIG. 30, and FIG. 31 are shown as discrete devices. The attenuatorsmay be separate components, or the attenuators may be integrated intothe radio, the ASD, the RF switch, or the antenna. The attenuators mayhave a fixed amount, adjustable or any varying amount of attenuation. Inone embodiment, attenuator is adjustable. The attenuators may includeany suitable software and/or hardware and incorporate digital signalprocessing. Although some enhanced antenna system embodiments includeattenuation, the embodiments are not limited to using hardwareattenuators. Moreover, the level of attenuation may be different fortransmission and reception.

An exemplary horn 266 is depicted in FIG. 35. A horn is best describedas cowbell shaped and hollow. The horn may be opened at a single end;however, depending on the type of antenna used or the type of antennacoverage desired, it may be open at both ends and possible one or moresides. An exemplary shape of the opening is rectangular; however, it mayalso be oval, square, triangular, polygon, or any other shape. A purposeof the horn is to, for example, at least one of decrease interferencebetween adjacent antennas, increase signal attenuation behind theantenna, enable any antenna type to function as a directional antenna,and provide control over the shape of the antenna's physical sector. Anexemplary material for the horn is metal-coated plastic; however, a hornmay be made out of metal, plastic, ceramic, semi-metals, compositematerials, graphite, glass, a combination of materials, and/or laminatedmaterials. A horn made from non-metallic materials may be coated withmetal, carbon, or some other material that reflects or absorbs RFenergy.

The horn material may be solid, but may also be a mesh, or a coatedmesh. The thickness of the material of the horn may be uniform orvariable. The cavity size may range from slightly larger than theantenna to many times larger than the antenna depending on the frequencyof operation and the desired area of coverage. The antenna may bemounted to the horn and the horn to its surroundings using any systemsand methods. The mounting method may be adjustable, so that the antennaposition within the horn may be adjusted, but the antenna position mayalso be fixed. The horn opening may be left uncovered, but it may alsobe covered partially or wholly with any type of material that does notsignificantly interfere with the radio waves. Such materials mayinclude, for example cloth, plastic, glass, plexi-glass, or any similarmaterial. In one embodiment, a single antenna is mounted in a horn, butmultiple antennas may be mounted in a horn. The RF reflecting orabsorbing material on the top and bottom of the horn may be removed toallow the antenna to broadcast and receive above and below its mountedposition. A horn with the top and bottom removed may still provideshielding from adjacent antennas as shown in FIG. 39.

A single, directional antenna 268 is mounted in horn 266 in FIG. 36 andFIG. 37 as viewed from the top in relation to FIG. 35. The effect ofantenna position in the horn is shown in FIG. 36 and FIG. 37. In FIG.36, the antenna is mounted farther from the opening than in FIG. 37. Theangular physical sector 270 of FIG. 36 is less than the angular physicalsector 272 of FIG. 37; thereby showing that the position of the antennain the horn influences physical sector shape and size. Anomni-directional antenna 274 is mounted in a horn 266 in FIG. 38. Thephysical sector shape and size of FIG. 38 may be substantiallyequivalent to the physical sector shape and size of FIG. 36; therebydemonstrating that the horn may enable any antenna type to function as adirectional antenna.

Multiple horns may be used together to shape wireless cell coverage. Sixhorns, each with one directional antenna, as shown in FIG. 39, providethe non-overlapping wireless cell coverage pattern of FIG. 41 when theantennas are positioned towards the back of the horn as shown in FIG.36. Moving the antennas to the front of the horns shown in FIG. 37results in the overlapping wireless cell coverage shown in FIG. 14.Multiple horns do not need to be positioned on the same horizontalplane. Horns may be placed above or below each other to provide thedesired wireless cell coverage pattern. Multiple horns may be mountedrelative to each other in any shape or pattern for producing the desiredwireless cell pattern. An exemplary relative positioning for about360-degree coverage by six antennas is shown in FIG. 39.

The enhanced antenna system introduced above related briefly to thehardware shown in FIG. 22 through FIG. 31 and to physical sectorcoverage patterns shown in FIG. 12 through FIG. 20, FIG. 32 through FIG.34, FIG. 42, and FIG. 44. While the enhanced antenna system considers,for example, the number of antennas, overlapping or non-overlappingantenna physical sectors, and the use and placement of attenuators, theenhanced antenna system is only part of a wireless cell. Radios are anadditional, indispensable part of a wireless cell. Other components of awireless cell may include, for example, at least one of RF switches,ASDs, processors, I/O ports, storage, attenuators in addition to thoseused in the enhanced antenna system, packet switches, horns, base bandprocessors, digital signal processors, and other analog or digitalelectronic components, or connections, and busses. No limitation isplaced on the number of radios, antennas, other components, or theorganization of the components in a wireless cell.

Various wireless cell hardware embodiments are presented in thisapplication. Wherever possible, the hardware embodiments are describedin terms of a previously described enhanced antenna system embodimentplus other components. The wireless cell hardware embodiments arespecific, non-limiting examples. Several hardware embodiments useconfigurations adapted for off-the-shelf radios that have an integratedRF switch known as a diversity switch. While the hardware embodimentstake advantage of component configurations inexpensively available onthe open market, the invention is not limited to components or componentconfigurations available on the open market.

In hardware embodiments that use attenuators or RF switches, theprocessor may control both thereby enabling the processor to adjustattenuation and the physical sector attached to the radio on aframe-by-frame basis to increase efficiency, increase performance,and/or decrease interference. In some instances, the radio may controlthe RF switch and the processor may control the attenuator, or it ispossible the radio may control both. If the attenuators are notvariable, neither the processor nor the radio may control them.

Wireless cell hardware embodiments may be shown with an optional I/Oport and local storage. An I/O port is a connection to a non-wirelessmedia and a protocol which may be different than the protocol used bythe wireless cell. For example, an I/O port connection may be at leastone of an Ethernet, infrared, USB, IEEE 1394, optical, or other type ofconnection. The presence of an I/O port may enable the wireless cell tofunction as an access point as described above. Local storage may becomposed of any type of storage including, for example, at least one ofRAM, ROM, flash, memory stick, hard disk drive, RW CDROM, or DVD. Localstorage may save on a temporary or permanent basis any type ofinformation including, for example, at least one of data, video, routingtables, processor code, or algorithms. An exemplary local storage may bea disk drive.

The wireless cell embodiments may use any protocol to communicate withother wireless cells, clients, or other wireless devices. Possiblecommunication protocols include, for example, at least one of 802.11a,802.11b, 802.11g, 802.15, 802.16, Bluetooth, and ultra-wideband. Anexemplary communication protocol is 802.11b/g.

The first hardware embodiment includes six antennas (118, 120, 122, 124,126, 128), three RF switches (130, 132, 134), three radios (136, 138,140), and one processor 142, as shown in FIG. 22, and uses the secondembodiment of an enhanced antenna system (overlapping physical sectors,no attenuators). In one embodiment, the RF switches 130, 132, and 134are integrated with radios 136, 138, and 140 respectively; however, theradios and RF switches may be separate. Either the radio or theprocessor may control the RF switches. The processor 142 sends andreceives data and control information to and from each radio. Asmentioned above, the first hardware embodiment may include I/O port 144and local storage 146. Furthermore, as described above, the firsthardware embodiment may implement the third, fourth, fifth and sixthantenna system embodiments if the attenuation is performed in theprocessor.

The second hardware embodiment includes six antennas (118, 120, 122,124, 126, 128), three RF switches (130, 132, 134), three ASDs (148, 150,152), three attenuators (154, 156, 158), three radios (136, 138, 140),and one processor 142, as shown in FIG. 23. The second hardwareembodiment uses the sixth embodiment of an enhanced antenna system(non-overlapping physical sectors, attenuator in the receive path). Inone embodiment, RF switches 130, 132, 134, ASDs 148, 150, 152, andattenuators 154, 156, 158 are integrated with radios 136, 138, and 140respectively; however, all the components may be separate. Theattenuators may include fixed or variable attenuation. The secondhardware embodiment may include I/O port 144 and local storage 146.

The third hardware embodiment is an exemplary wireless cell embodiment.The third hardware embodiment is similar to the second hardwareembodiment except the third hardware embodiment, for example, uses thefourth embodiment of an enhanced antenna system (overlapping physicalsectors, attenuator in the receive path). The third hardware embodimentmay include I/O port 144 and local storage 146.

The fourth hardware embodiment includes six antennas (118, 120, 122,124, 126, 128), six attenuators (166, 168, 170, 172, 174, 176), three RFswitches (130, 132, 134), three radios (136, 138, 140), and oneprocessor 142, as shown in FIG. 24. The fourth hardware embodiment usesthe fifth embodiment of an enhanced antenna system (non-overlappingphysical sectors, attenuator next to the antenna). In one embodiment, RFswitches 130, 132, 134, are integrated with radios 136, 138, and 140respectively; however, the radios and RF switches may be separate. Theattenuators may be of fix or variable attenuation. The fourth hardwareembodiment may include I/O port 144 and local storage 146.

The fifth hardware embodiment is similar to the fourth hardwareembodiment except the fifth hardware embodiment, for example, uses thethird embodiment of an enhanced antenna system (overlapping physicalsectors, attenuator next to the antenna). The fifth hardware embodimentmay include I/O port 144 and local storage 146.

The sixth hardware embodiment includes four antennas (about 180, 182,184, 186), two RF switches (188, 190), two radios (192, 194), and oneprocessor 196, as shown in FIG. 25, and uses the second embodiment of anenhanced antenna system (overlapping physical sectors, no attenuators).In one embodiment, the RF switches 188, and 190 are integrated withradios 192 and 194, respectively; however, the radios and RF switchesmay be separate. The processor 196 sends and receives data and controlinformation to and from each radio. As mentioned above, the sixthhardware embodiment may include I/O port 198 and local storage 200.

The seventh hardware embodiment includes four antennas (about 180, 182,184, 186), two RF switches (188, 190), two ASDs (202, 204), twoattenuators (206, 208), two radios (192, 194), and one processor 196, asshown in FIG. 26. The seventh hardware embodiment uses the sixthembodiment of an enhanced antenna system (non-overlapping physicalsectors, attenuator in the receive path). In one embodiment, RF switches188, 190, ASDs 202, 204, and attenuators 206, 208 are integrated withradios 192, and 194 respectively; however, all the components may beseparate. The attenuators may be of fixed or variable attenuation. Theseventh hardware embodiment may include I/O port 198 and local storage200.

The eighth hardware embodiment is similar to the seventh hardwareembodiment except the eighth hardware embodiment, for example, uses thefourth embodiment of an enhanced antenna system (overlapping physicalsectors, attenuator in the receive path). The eighth hardware embodimentmay include I/O port 198 and local storage 200.

The ninth hardware embodiment has four antennas (about 180, 182, 184,186), four attenuators (210, 212, 214, 216), two RF switches (188, 190),two radios (192, 194), and one processor 196, as shown in FIG. 27. Thefourth hardware embodiment uses the fifth embodiment of an enhancedantenna system (non-overlapping physical sectors, attenuator next to theantenna). In one embodiment, RF switches 188, and 190, are integratedwith radios 192 and 194, respectively; however, the radios and RFswitches may be separate. The attenuators may be of fixed or variableattenuation. The ninth hardware embodiment may include I/O port 198 andlocal storage 200.

The tenth hardware embodiment is similar to the ninth hardwareembodiment except the tenth hardware embodiment, for example, uses thethird embodiment of an enhanced antenna system (overlapping physicalsectors, attenuator next to the antenna). The tenth hardware embodimentmay include I/O port 198 and local storage 200.

Now turning to exemplary client embodiments. Performance of any clientmay be improved by using an enhanced antenna system embodiment to reduceinterference. As mentioned in the first embodiment of an enhancedantenna system, a client generally uses only one antenna andcommunicates with a single device at a time because clients generallyhave only one radio. Although an enhanced antenna system may be adaptedto enable only a single antenna at a time, enhanced antenna systems donot limit a client to one radio, or to using only one antenna at a time.

Each embodiment described below shows a single radio and assumes thatonly one antenna is active a time; however, the embodiments may includeany number of antennas available, any number of antennas in simultaneoususe, any number of radios, overlapping or non-overlapping physicalsectors, physical sector positioning, and/or communication protocolsused. In the embodiments described, the radio may measure receive signalstrength, or signal quality, through each available antenna then may useonly the antenna that delivers the highest quality signal. The frequencyof testing all antennas to determine which one provides the highestquality signal may be accomplished, for example, periodically by fixedor random interval, after each transmission, after each frame, ascommanded by the wireless cell, when the signal strength of the receivesignal decreases below a predetermined threshold, or any at any othertime.

An exemplary client embodiment may include two antennas, anoff-the-shelf, cost-effective radio with an integrated RF switch(diversity switch), and uses the first embodiment of an enhanced antennasystem; however, other hardware arrangements are possible. An exemplaryclient uses the 802.11 protocols and interfaces to a wireless cell thatuses the same 802.11 protocols; however, any other protocol for bothclient and wireless cell may be used. An exemplary client also usesextensions to the 802.11 protocols to communicate control informationand requests to the wireless cell to improve data throughput,transmission signal strengths, noise suppression, and other performancefactors. The RF switch may be controlled by the radio (especially if theRF switch is integrated with the radio); however, selection of theantenna by the RF switch may also be controlled by, for example, theclient, the wireless cell by way of command, or manually.

The first client embodiment may include two antennas (218, 220), one RFswitch (222), one radio (224), and the client (226) as shown in FIG. 28.The first client embodiment uses the first embodiment of an enhancedantenna system. In one embodiment, the first embodiment of the enhancedantenna system when used with the first client embodiment is arranged toprovide about 360-degree coverage, but it is not required. The firstclient embodiment using the first embodiment of an enhanced antennasystem may provide the coverage patterns shown in FIG. 19, FIG. 32, orany other pattern of two non-overlapping physical sectors. In oneembodiment, the RF switch 222 is integrated with the radio 224 and isavailable as an off-the-shelf component, but integration is notrequired. The first client embodiment may alternately use the secondembodiment of an enhanced antenna system to allow overlapping physicalsectors; however, only one antenna may be enabled at a time.

The second client embodiment may include two antennas (218, 220), one RFswitch (222), one ASD (228), one attenuator (230), one radio (224), andthe client (226), as shown in FIG. 30. The second client embodiment issimilar to the first client embodiment except it uses the sixthembodiment of an enhanced antenna system (non-overlapping physicalsectors, attenuator in the receive path). The sixth embodiment of anenhanced antenna system allows the second client embodiment to attenuatethe receive signal to reduce interference from unwanted sources. In oneembodiment, the RF switch 222, the ASD 228, and the attenuator 230 areintegrated with the radio 224, but integration is not required. Theattenuator may be of fixed or variable attenuation. In one embodiment,the attenuator is variable and controlled by the client on a per framebasis; however, the attenuator may also be controlled by the radio anduse any algorithm or frequency of adjustment. The second clientembodiment may alternately use the enhanced antenna system fourthembodiment to allow overlapping physical sectors; however, only oneantenna may be enabled at a time.

The third client embodiment is similar to the first client embodimentexcept, for example, the third client embodiment has four antennasinstead of two. The third client embodiment has four antennas (232, 234,236, and 238), one RF switch (240), one radio (242), and the client(244) as shown in FIG. 29. The third client embodiment uses the enhancedantenna system first embodiment. In one embodiment, the first embodimentof the enhanced antenna system when used with the third clientembodiment is arranged to provide about 360-degree coverage, but it isnot required. The third client embodiment using the enhanced antennasystem of the first embodiment may provide the coverage patterns shownin FIG. 16, or any other pattern of four non-overlapping physicalsectors. The physical sectors are not required to be adjacent. In oneembodiment, the RF switch 240 is integrated with the radio 242 and isavailable as an off-the-shelf component, but integration is notrequired. The third client embodiment may also use the enhanced antennasystem second embodiment to allow overlapping physical sectors; however,only one antenna may be enabled at a time.

The fourth client embodiment may be similar to the second clientembodiment except, for example, the fourth client embodiment has fourantennas instead of two. The fourth client embodiment has four antennas(232, 234, 236, and 238), one RF switch (240), one ASD (246), oneattenuator (248), one radio (242), and the client (244), as shown inFIG. 31. The fourth client embodiment uses the enhanced antenna systemsixth embodiment. In one embodiment, the sixth embodiment of theenhanced antenna system is arranged to provide about 360-degreecoverage, but it is not required. The fourth client embodiment using theenhanced antenna system sixth embodiment may provide the coveragepattern shown in FIG. 16, or any other pattern of four non-overlappingphysical sectors. The physical sectors are not required to be adjacent.The enhanced antenna system sixth embodiment also allows the fourthclient embodiment to attenuate the receive signal to reduce interferencefrom unwanted sources. In one embodiment, the RF switch 240, the ASD246, and the attenuator 248 are integrated with the radio 242, butintegration is not required. The attenuator may be of fixed or variableattenuation. In one embodiment, the attenuator is variable andcontrolled by the client on a per frame basis; however, the attenuatormay also be controlled by the radio and use any algorithm or frequencyof adjustment. The fourth client embodiment may alternately use theenhanced antenna system fourth embodiment to allow overlapping physicalsectors; however, only one antenna may be enabled at a time.

As discussed, the invention may include off-the-shelf components toreduce cost, hasten development, speed production, and to ensure qualityand reliability. Radios with integrated diversity switches are readilyavailable and processor development boards are useful for softwaredevelopment platforms; however, the radios, processor board, antennas,horns and any other component must be integrated together to form thewireless cell. An exemplary method of integration is to develop aprinted circuit board (PCB) to house the radios with any additionalcomponents such as attenuators. The radio board then couples to theprocessor board and to the antennas. Components such as I/O port andlocal memory may be incorporated into the processor board. The interfacebetween the processor board and the radio PCB is generally not timingcritical or sensitive to noise because the processor connects to theradios using an industry standard bus such as PCI, USB, PC Card, or IEEE1394 depending on the radio interface bus. The wiring of the radio PCB;however, is highly sensitive because multiple radios and radio frequencycables are in close proximity. Radios may be placed in shield cans. Thewires from the radios to the antennas or to the horns containing theantennas may be placed away from each other to reduce crosstalk andinterference. Wires between components may be shielded.

Now turning to exemplary channel assignment methods. Radios transmit andreceive through antennas using specific channels. A channel may consistsof, for example, specific radio frequency or frequencies, encoding anddecoding schemes, modulating and demodulating schemes, and other methodsto enable a channel to send and receive information. When two radiostransmit on the same channel in the same physical area, thetransmissions interfere with each other. As mentioned earlier, somechannels do not interfere or minimally interfere with each other whenused in the same physical location. Multi-sector wireless cells,especially those that use overlapping physical sectors, may useminimally interfering channels to enable multiple radios to transmit andreceive simultaneously in the same physical area with less interference.The number of channels needed to reduce interference between physicalsectors depends on, for example, the number and arrangement of thephysical sectors. Other factors that influence the assignment ofchannels may include, for example, the channels used by close, foreignwireless cells, multi-path interference, client transmit signalstrength, reflected signals, signal attenuation behind the antenna, hornsignal attenuation, antenna side lobes, and other factors.

In general, an exemplary approach to assigning channels is to assignminimally interfering channels to adjacent, non-overlapping physicalsectors and to overlapping physical sectors. Several channel assignmentsmay be possible for every wireless cell coverage pattern. It is alsopossible to use time multiplexing techniques to reduce interferencebetween adjacent or overlapping physical sectors that for whateverreason use the same channel. Some options for assigning channels arediscussed for both overlapping and non-overlapping wireless cellcoverage patterns. Some examples apply to the hardware and enhancedantenna system embodiments disclosed. The assignment methods disclosedare not to be construed as a limitation on methods of assigning channelsto wireless cell coverage patterns.

The diagrams showing exemplary channel assignments use the alphanumericidentifiers C1, C2, etc. to represent channels. The identifiers C1, C2,etc. do not represent a specific channel. Any channel may be assigned tothe identifier C1, but the same channel is assigned to every physicalsector labeled C1. While C1 and C2 do not necessarily represent specificchannels, C1 represents a channel that may be different from and may beminimally interfering with the channel represented by C2. The same rulesapply to all channel identifiers.

Several exemplary wireless cell coverage patterns and possible channelassignments are shown in FIG. 40 through FIG. 50. The examples are notexhaustive, but are representative of how channels may be assigned toreduce interference. The channel assignment shown in FIG. 40 may be usedfor three physical sectors, non-overlapping, about 360-degree wirelesscell coverage. Using three channels as shown in FIG. 40 allows theradios attached to the antenna physical sectors 62, 64, and 66 tooperate independently and simultaneously with minimal interference toeach other. Another possible channel assignment may be to use C1 toprovide time-multiplexed coverage of physical sectors 64 and 66. Undersuch a scheme, C2 operates continuously in physical sector 62 while C1may operate exclusively for some period in physical sector 64 thenoperates exclusively in physical sector 66. C1 may also providetime-multiplexed coverage in all three sectors 62, 64, and 66.

Another potential channel assignment option is to assign the samechannel to all three physical sectors 62, 64, and 66 shown in FIG. 40.Directional antennas or horns form the wireless coverage pattern shownin FIG. 40. As discussed above, directional antennas experience someattenuation between their operational center and the edge of theirphysical sector; therefore, even if adjacent physical sectors use thesame channel, the attenuation of the signal at the edge of the physicalsector may reduce the amount of interference between adjacent sectors.Increasing the amount of attenuation from the antenna's operationalcenter to the physical sector edge may further decrease the interferencebetween adjacent sectors that use the same channel.

The six physical non-overlapping sectors which form about 360-degreewireless cell coverage patterns in FIG. 41, FIG. 42, and FIG. 43 usetwo, three, and six minimally interfering channels, respectively.Clearly, other assignments that maintain different channels for adjacentphysical sectors are possible such as modifying the channel assignmentsof FIG. 42 such that C1, C2, C3, C2, C1, and C3 are assigned to physicalsectors 282, 284, 286, 276, 278 and 280 respectively. As mentionedabove, time-multiplexed techniques or antenna attenuationcharacteristics may decrease the number of channels used while stillreducing interference between adjacent physical sectors.

The non-overlapping wireless cell coverage patterns shown in FIG. 44,FIG. 45, FIG. 46, FIG. 47, and FIG. 48 use similar principles to assignchannels to coverage patterns less than 360 degrees. The patterns shownmay be varied while still maintaining different channels in adjacentphysical sectors. Time-multiplexing and antenna characteristics mayreduce the number of channels used. The pattern shown in FIG. 49 may usethe same channel for both physical sectors because they are not adjacentand the directional antenna characteristics help reduce interferencebetween the physical sectors. Two different channels may also be used.The channel assigned to an isolated physical sector, as shown in FIG.50, does not have to consider adjacent physical sectors but must stillconsider the other factors mentioned above such as channel assignment offoreign wireless cells, multipath interference, etc.

An exemplary approach to assigning channels to coverage patterns thathave overlapping physical sectors is to assign different, minimallyinterfering, channels to adjacent physical sectors and to overlappingphysical sectors. An example of assigning three channels to a sixphysical sectors, six virtual sectors, about 360-degree wirelesscoverage pattern is shown in FIG. 51, FIG. 52, and FIG. 53. The sixphysical sectors are shown in two groups of three non-overlappingphysical sectors in FIG. 51 and FIG. 52. Each adjacent physical sectoris assigned a different channel to minimize interference. In oneembodiment, the physical sectors are the same or similar size andoriented such that each physical sector substantially equally overlapstwo adjacent physical sectors. Various overlap and physical sector sizeschemes are possible; however, using physical sectors of substantiallyequal size and overlapping by about 50% provides symmetry, substantiallyequally sized virtual sectors, and positions the operational center ofan antenna over the edges of two adjacent physical sectors.Superimposing the physical sectors of FIG. 51 and FIG. 52 whilemaintaining their respective orientations results in the overlappingwireless cell coverage pattern shown in FIG. 53. No overlapping physicalsector has the same channel as the physical sectors it overlaps. Eachvirtual sector receives coverage from two different channels.

The same approach may be used for wireless coverage patterns less thanabout 360 degrees. FIG. 54 and FIG. 55 show non-overlapping coveragepatterns and channel assignments, that when superimposed, form theoverlapping wireless coverage pattern shown in FIG. 56. Adjacentphysical and overlapping physical sectors may include different,minimally interfering, channels assigned while each virtual sector iscovered by two radios using different channels. Physical sectors may notbe limited to similar size as mentioned above and as shown in FIG. 55.

The channel assignments shown in FIG. 53 and FIG. 56 are two embodimentsof many potential channel assignments. Many combinations of channelassignments exist that produce an exemplary situation where adjacent andoverlapping sectors use different channels.

While it is possible for adjacent physical sectors to use the samechannel and rely on antenna characteristics or placement to minimizeinterference, overlapping physical sectors may be not assigned the samechannel. It may be possible to assign physical sectors 56, 58, and 60 ofFIG. 51 to the same channel and physical sectors 62, 64, and 66 of FIG.52 to a different channel and still reasonably limit interferencebetween adjacent physical sectors through antennas characteristics andplacement. Time-multiplexing techniques also allow any number ofchannels to provide coverage with minimal interference.

The hardware shown in FIG. 22, FIG. 23, or FIG. 24 may produce thewireless coverage pattern and channel assignments shown in FIG. 53 byusing the second, fourth, and fifth enhanced antenna embodimentsrespectively. Each radio 136, 138, and 140 is set to a channel. Theantennas may need angle of coverage of approximately 120 degrees. Thepattern of FIG. 53 may be achieved by positioning the antennas attachedto a radio so that the operational centers of their physical sectors aresubstantially diametrically opposed. For example, if radio 136, 138, and140 are set to channels C1, C2, and C3 respectively, antennas 118 and120 may be assigned to substantially correspond to physical sectors 56and 64, antennas 122 and 124 to substantially correspond to physicalsectors 58 and 66, and antennas 126 and 128 to substantially correspondto physical sectors 60 and 62. Other variations of radio channelassignments and antenna physical sector positioning exist.

The hardware shown in FIG. 22, FIG. 23, or FIG. 24 may also produce thewireless cell coverage pattern shown in FIG. 42. The hardware in FIG. 23and FIG. 24 may use the sixth and fifth enhanced antennas systemembodiments respectively. The antennas may need an angle of coverage ofapproximately 60 degrees. If radio 136, 138, and 140 are set to channelsC1, C2, and C3 respectively, antennas 118 and 120 may be positioned tosubstantially correspond to physical sectors 276 and 282; antennas 122and 128 to substantially correspond to physical sectors 278 and 284, andantennas 126 and 128 to substantially correspond to physical sectors 280and 286. Other variations of radio channel assignments and antennaphysical sector positioning exist.

Using the same approach, the hardware of FIG. 25, FIG. 26, or FIG. 27may produce the wireless cell coverage pattern and channel assignment ofFIG. 44. The hardware in FIG. 26 and FIG. 27 may use the sixth and fifthenhanced antenna system embodiments, respectively. A hardwareconfiguration where a radio attaches to three antennas through an RFswitch may produce the coverage and channel assignment of FIG. 41. Thepattern shown in FIG. 43 may be produced by hardware, wherein forexample, six radios may each service their own single antenna, or sixradios may connect to six antennas through an RF switch. The wirelesscell pattern and channel assignment of FIG. 56 may be produced byhardware where one radio supports three antennas and two other radioseach support two antennas, or by hardware where seven radios are eachattached to one antenna, or by hardware where four radios each supporttwo antennas, but one of the antennas is not used. The wireless cellcoverage patterns, channel assignments, and hardware are merely a fewexamples of many possible variations.

Now turning to exemplary methods of use. Signal quality is a term usedto describe radio signals wherein higher quality signals typically moreaccurately transmit and receive information, and provide higher datatransfer rates (i.e., throughput). In contrast, lower quality signalspotentially suffer losses in transmission and reception; therebyresulting in low throughput. Signal quality is a measure of, forexample, signal level, noise level, error rate, and other operationaland environmental factors from a radio's perspective. Each radiomanufacturer determines a proprietary measure of signal quality andassigns a relative number. Most manufacturers determine signal qualityin a different way, so the quality numbers from different radiomanufacturers often cannot be meaningfully compared to each other. Thesignal quality of radios from the same manufacturer may be compared todetermine which radio receives the highest or lowest quality signal,wherein such signal quality may be determined for each channelavailable.

A radio may perform a signal quality scan by listening to receivesignals and ranking them by their signal quality. Radios may be capableof using more than one channel scan and ranking all signals received onall channels. In one embodiment, a signal quality scan may be used bywireless cells, clients and other wireless devices to detect foreignwireless cells, access points, clients or other wireless devices.

A wireless cell may perform a traffic load scan by setting its radiosinto the receive mode and counting the number of frames or the amount oftraffic sent by foreign wireless cells on all possible channels. Atraffic scan reveals the traffic load on each channel and the signalquality of the channels used by the detected foreign wireless cells.Traffic load information may be used when assigning channels to physicalsectors. In one embodiment, the channel assigned to a specific physicalsector is one where the foreign wireless cell traffic load and signalquality is low.

Wireless communication typically cannot take place between a wirelesscell and a client until a relationship is established. In the simplestsetting, a client requests to associate with a wireless cell, and if thewireless cell grants the association, a relationship is established andcommunication may occur. A client may not only associate with thewireless cell, but also with a specific physical sector of the wirelesscell. Client CL3 in FIG. 57 detects radio signals from physical sectors288, 290, 292, and possibly from 294. Client CL3 makes a request toassociate with one of the physical sectors 288, 290, 292, or 294,generally based on the quality of the signal CL3 receives from eachsector. The wireless cell 296 may either accepts or denies the request.If the request is denied, client CL3 may request association with adifferent sector. The process may continue until client CL3 eitherassociates with a physical sector of wireless cell 296 or until allrequests are denied. Wireless cell 296 may track the clients serviced byeach physical sector.

The wireless cell may deny client association with one physical sectorin preference of another physical sector to balance the loading and/orto improve the data transfer rates of the clients among the physicalsectors. Client CL3 in FIG. 57 will most likely associate with and beserviced by physical sector 290; however, a reflection of the signalfrom physical sector 294 may provide the best signal quality and clientCL3 may seek to instead associate with, for example, physical sector294. Although environmental conditions may affect the association andservicing of clients, increasing the number of physical sectors of awireless cell generally increases the number of association and loadbalancing possibilities.

Overlapping physical sectors provide additional association and loadbalancing options. Referring to FIG. 14 and FIG. 58 together, clientCL12 lies within physical sectors 64 and 58, which is also labeled asvirtual sector 72. The wireless cell may balance its load by denyingclient CL12 association with physical sector 58, but by acceptingassociation with physical sector 64; thereby leaving physical sector 58to help service clients CL10, and/or CL11. Wireless cell 298 may spreadthe load of CL10, CL11, CL17, and CL18 between physical sectors 58, 62,and 56.

Simple clients may be capable of associating. Advanced clients may sendinformation to the wireless cell during the association process. Anadvanced client may report, for example, at least one of its desiredminimum and maximum throughput needs, desired channel, signal qualityfor all channels, all detectable wireless cells and physical sectors,physical distance to all wireless cells, local storage capacity,additional available communication protocols, ability to physicallymove, or any other information useful to the wireless cell in servicingthe client. Exemplary protocols for simple clients are the 802.11communications protocols.

The channel used between the wireless cell and the client may also beestablished at association. The wireless cell may change the channelsassigned to its physical sectors in response to, for example,interference, loading, throughput demands, or other factors. In oneembodiment, when the wireless cell changes the channel used in aphysical sector, all clients associated with the physical sectordetected, and follow to the new channel. Advanced clients may be capableof either negotiating the use of a different channel, or providing thewireless cell with signal quality information from each client'sperspective to assist the wireless cell in determining the best channelsto use.

A wireless cell may dynamically balance its load by disassociating aparticular client with a particular physical sector and accepting anassociation with a different sector, or the wireless cell may usecontrol commands to move an advanced client to a different physicalsector and different channel without requiring the client to repeat theassociation process. A client may disassociate with its current physicalsector and request association with another physical sector of the samewireless cell, but in one embodiment, the wireless cell approves the newassociation request.

During an active scan, the wireless cell scans all or most channels onall or most radios and through all or most antennas. Active scans mayperform both signal quality and traffic load scans, and may detect allor most active, foreign wireless cells operating on any channel. Anactive scan may disrupt transmission and reception of normal data andcontrol information with associated clients that is in progress. Activescans may be performed at initialization or when a radio is inactive fora predetermine amount of time. One method of performing an active scanis shown in FIG. 61 in which all radios are set to the same channelsimultaneously and allowed to collect signal quality information. Thesignal quality collected from each radio may be used to determinepotential channel assignments for each radio to substantially complywith throughput, or loading specifications.

A passive scan may not disrupt transmission and reception of normal dataand control information. Passive scans are often performed on a radiobetween data transmission and reception and may be limited to thechannel in use by the radio. Passive scans may also perform both signalquality and traffic load scans. Generally, the radio may continuouslyperform passive scans collecting information such as wireless cellidentification numbers, frame received, and frames transmitted. Aspermitted by the communication protocol and loading, the processor pollsthe radio to read the information the radio collects during its passivescans. Passive scans also detect any newly active foreign wireless cellsoperating on the same channel as the scanning radio that were notdetected during the most recent active scan. When using exemplarycommunication protocols, 802.11, new foreign access points may bedetected when the new access point sends its beacon.

The operation of a wireless cell and the method in which it servicesclients may depend on, for example, at least one of the number ofradios, number of antennas, arrangement of antenna physical sectors,hardware components and organization, detectable foreign wireless cells,number of clients, client throughput demand, and a variety of otherfactors. An exemplary operating scenario is shown in FIG. 57. For thisexample, assume the non-overlapping wireless cell 296 coverage patternshown in FIG. 57 is produced using the hardware shown in FIG. 26.Physical sectors of antennas 180, 182, 184, and 186 substantiallycorrespond to physical sector positions 288, 292, 290, and 294respectively. Radio 192 services physical sectors 288 and 292 throughantennas 180 and 182 respectively and is set to channel C1. Radio 194services physical sectors 290 and 294 through antennas 184 and 186respectively and is set to channel C2. Clients CL1 and CL2 areassociated with and serviced by radio 192 through antenna 180 that formsphysical sector 288. Clients CL4 is associated with and serviced byradio 192 through antenna 182 that forms physical sector 292. Client CL3is associated with and serviced by radio 194 through antenna 184 thatforms physical sector 290. Clients CL5 and CL6 are associated with andserviced by radio 194 through antenna 186 that forms physical sector294. Client CL7 is not associated with any physical sector of wirelesscell 296, but transmissions from CL7 are detectable by the wirelesscell. Assume for the example that CL7 transmits on channel C1 with asignal of the same quality and strength as client CL4.

Radio 192 may not simultaneously service physical sectors 288 and 292.The same may apply to radio 194 and physical sectors 290 and 294.Therefore, the wireless cell 296 may simultaneously service one clientfrom the group of clients CL1, CL2, and CL4 and one client from thegroup of clients CL3, CL5, and CL6. For example, client CL3 may transmitwhile CL4 simultaneously receives. If CL1 wants to send data to CL2,wireless cell 296 must first receive the data from CL1, store itlocally, and then forward it to client CL2. The communication protocolused may determine how data is packaged for transmission and reception.Exemplary communication protocols may use packets or frames, which allowthe radios to service client demand in manageable, discrete chunks. Anyalgorithm may be used to control switching the radio between the sectorssuch as time multiplexing, past client demand, expected client demand,or throughput allocation. In one embodiment, the radios passively scantheir respective physical sectors through the appropriate antenna todetect and service client communications requests.

Although client CL7, in FIG. 57, may not be associated with any physicalsector or either radio 192 or 194, transmissions from CL7 interfere withCL4 and possibly CL1 and CL2. The hardware shown in FIG. 26 is equippedwith an attenuator in the receive path of either radio. Increasing theattenuation of attenuator 206 each time radio 192 services physicalsector 292 may reduce the interference of CL7. Increasing theattenuation decreases the received signal strength of both CL4 and CL7;however, if CL4 and CL7 transmit with the same signal quality andstrength, the signal from CL7 may be attenuated more than the signalfrom CL4 because CL7 is farther away. The attenuator is set to a levelwhere CL7 interference is negligible, yet the signal from CL4 is stillreliably received. In one embodiment, the attenuator may be controlledon a per packet or frame basis, thereby allowing the processor or theradio to increase the attenuation factor only when servicing client CL4in physical sector 292.

Similar to the non-overlapping wireless cell described above, theoperation of an overlapping wireless cell depends on many factors, butthe virtual sectors formed by overlapping physical sectors may improveperformance and flexibility because each virtual sector may be servicedby at least two independent radios. A potential operating scenario foran overlapping wireless cell is shown in FIG. 58. Assume for thisexample that the overlapping wireless cell coverage pattern of FIG. 58is produced using the hardware shown in FIG. 22. Referring also to FIG.53, physical sectors of antennas 118, 120, 122, 124, 126, and 128substantially correspond to physical sector positions 56, 64, 58, 66,60, and 62. Therefore, radio 136 uses channel C1 and services virtualsectors 68, 72, 74, and 78. Radio 138 uses channel C2 and servicesvirtual sectors 70, 72, 76, and 78. Radio 140 uses channel C3 andservices virtual sectors 68, 70, 74, and 76.

A notable difference between an overlapping and non-overlapping wirelesscoverage pattern is that each client may potentially, depending onchannel assignments, associate with one of at least two radios. If avirtual sector is formed by more than two overlapping physical sectors,a client may potentially associate with one of many radios. In thescenario of FIG. 58 and when the hardware of FIG. 22 is used, eachclient of wireless cell 298 may associate with one of two radios thatservice each virtual sector. The combinations of client-to-radioassociations are numerous; however, any two clients in a virtual sectormay associate with and be serviced by different radios, which means thattwo clients in any virtual sector may be serviced simultaneously. Forexample, assume client CL10 associates with radio 138 using channel C2while client CL11 associates with radio 140 using channel C3. Becausethe channels are different and minimally interfering, CL10 and CL11,which are in the same virtual sector, may communicate to each other orto other devices simultaneously.

As with the non-overlapping example given above, the hardwareconfiguration of FIG. 22 may be utilized such that, each radio mayservice only one physical sector, which translates to one virtualsector, at a time. Therefore, while radio 138 services a client invirtual sector 70, it may not be servicing clients in virtual sectors72, 76, or 78. Communications between virtual sectors may occursimultaneously if the clients are serviced by different radios, butcommunications between clients serviced by the same radio must occursequentially instead of simultaneously. For example, if client CL17 andCL13 are both associated to radio 136, communications between them mustoccur sequentially. If, at the same time, client CL18 is associated withradio 140, communications between CL18 and CL13 may occursimultaneously.

In one embodiment, the radios passively scan their respective physicalsectors to detect and service client communications requests. Anexemplary communication algorithm may include an algorithm that usespackets or frames, thereby allowing the wireless cell to efficientlymanage client requests for service.

Although many factors affect communication between a wireless cell and aclient, a client with an enhanced antenna system may disable antennas oradjust receive attenuation to better cope with interference. FIG. 59shows three exemplary wireless cells 300, 302, and 306, which areforeign to each other, and an exemplary two-sector client 304. Assumeclient 304 uses the second client embodiment as shown in FIG. 30. Forthe situation shown in FIG. 59, assume that sector 308 of wireless cell300 uses channel C1 and provides the highest quality signal possible toclient 304. Assume also that omni-directional wireless cell 302 and aphysical sector of wireless cell 306 also provide strong signals onchannel C1, but they may not be as strong as the signal from wirelesscell 300 as perceived by client 304. In this example, the client 304elects to use the highest quality signal it perceives and thereforeassociates with wireless cell 300. Using the enhanced antenna approachdisclosed for clients, client 304, disables the antenna servicingphysical sector 312. The antenna servicing physical sector 310 may bedirectional and attenuates signals from behind; therefore, disabling theantenna servicing physical sector 312 immediately reduces the effect ofradio signals from wireless cell 306 on client 304. The client 304 mayreduce the effects of interference from wireless cell 302 by increasingthe amount of attenuation in its receive path. Increasing theattenuation decreases the receive signal strength of the signals fromboth wireless cells 300 and 302; however, the signal from 300 is higherquality and stronger than the signal from 302, so client 304 increasesattenuation until interference from wireless cell 302 is negligiblewhile at the same time the signal from wireless cell 300 is stillintelligible.

In another example, referring to FIG. 59, assume client 304 desires toassociate with exemplary cell 306. Assume also that exemplary cell 300provides, as in the last example, the highest quality signal. In such asituation, physical sector 312 of wireless cell 304 may associate with asector of wireless 306 even though wireless cell 300 may offer a higherquality signal. Once wireless cell 304 associates with wireless cell306, wireless cell 304 may disable physical sector 310 to disableinterference from wireless cells 300 and/or wireless cell 302.

Assume a similar situation applies in FIG. 60 as described for FIG. 59except that, for example, the client 314 is implemented using the thirdclient embodiment as shown in FIG. 29. As above, the client 314 electsto associate with wireless cell 300 because it provides the highestquality signal. Client 314 then disables the antennas servicing physicalsectors 318, 320, and 322; thereby reducing the interference fromwireless cells 306 and 302. Interference from wireless cell 302 isreduced due to the directional characteristics of the antenna servicingphysical sector 316 and not through attenuation in the client receivepath. The increased number of sectors in client 314, over client 304,provides client 314 with more options when dealing with interference.Client 314 may also be implemented using client embodiment four, asdepicted in FIG. 31, which may allow the client to adjust the attenuatorto further cope with interference from wireless cell 302. Clientembodiments have no limit on the number of antennas.

After the client associates with a wireless cell and disables the unusedantennas, it may occasionally scan all antennas to determine if a higherquality signal has become available from another wireless cell. Anelapse of time, loss, or deterioration of signal, or any other eventsuch as a change in position of the client may also trigger scanningthrough the disabled antennas. If a scan reveals a higher qualitysignal, the client may associate with the wireless cell providing thebetter signal, disable the antennas not in use, and possibly readjustthe attenuator. During the scan, the attenuation of the attenuator maybe decreased to zero.

As discussed above when discussing client association, clients may havevaluable information to share with the wireless cell. Advanced clientsmay report such information as, for example, desired minimum and maximumthroughput needs, desired channel, signal quality for all channels,other detected wireless cells or physical sectors, physical distance toall wireless cells, local storage capacity, additional availablecommunication protocols, ability to move, active or passive scanresults, local storage fullness levels of empty, full, high water markor low water mark, current channel signal quality, request for channelchange or other environmental, and/or operational information. In turn,the wireless cell may send information or commands to advanced clientsto facilitate, for example, changing channels, changing protocols,authenticating the client, requesting signal quality information fromthe client perspective, moving a client to another physical sector,and/or any other type of action. Communication of control orenvironmental information between a wireless cell and advanced clientsmay occur at association, during active or passive scans, or at any timeallowed by the communication protocol.

Throughput load management may be considered a step beyond loadmanagement described above. Throughput load management attempts toassign resources according to client throughput specifications. Thewireless cell determines each client's desired throughput by, forexample, at least one of direct user input, polling during active orpassive scan, look up preprogrammed information, monitoring trafficduring operation, and/or any other means. In addition to clientthroughput, each client may provide the wireless cell with a prioritizedlist of optimal channels from the clients' perspective. The wirelesscell then determines the optimal way to meet all client needs using theavailable resources.

An exemplary division of resources may assign one high throughput clientper radio using its optimal channel. In another embodiment, lowerthroughput clients may be assigned to the same radio as a highthroughput client, but receive lower priority service. Another approachis to service as many low throughput clients as possible with a singleradio; thereby leaving the other radios available to service highthroughput clients. As discussed above in the section on clientassociation, if a change of conditions include the wireless cell tochange the channels used in any physical sector, the clients follow thechannel change.

The wireless cell may use the passive scan or any other means tocommunicate with each client to ensure that each client has itsthroughput demands fulfilled. In one embodiment, each client includes alocal buffer and may communicate levels of buffer capacity to thewireless cell. The size of the buffer is dependant on the link quality,and may either be statically allocated (e.g., 500-1000 frames) ordynamically allocated, so that the buffer size grows as the link qualitydecreases. When client demand is not met, the wireless cell may, forexample, at least one of scan for channels with higher quality signalcapable of providing higher throughput, poll the clients to determine ifthroughput needs have change, change channels to attempt improvement indata throughput, and determine how to assign resources to meetthroughput specifications. Any changes in channel, association, orhardware assignments are then implemented. In the situation where awireless cell streams video to a client with a local buffer, changingchannel may not affect the video stream because the local buffer mayreceive a retransmission of the affected frames before they are desiredfor display.

A wireless cell may use any or all of the techniques discussed above toincrease the success of streaming video in addition to servicing otherclients. The wireless cell may perform, for example, an active scan todetermine signal quality for each channel, sources of interference, thepresence of foreign wireless cells or access points, and any otherpotential environmental information. The wireless cell then determines,for example, at least one of the number of clients that want toassociate, each client's throughput specifications, which physicalsectors may service each client, the best channels for each client, andother client related information. The wireless client may gather anyenvironmental, system, or performance information from each client suchas, for example, at least one of channel signal quality from theperspective of the client, buffer size, desired channel, and any otherinformation available from the client. The wireless cell performs itsload and throughput-load calculations, allocates resources, allows, orcommands the clients to associate, then starts operation. The wirelesscell may continually monitor the channels, clients, and other factors,such as buffer capacity levels of each client, during operation todetermine if throughput specifications are being met. If throughputneeds are not being met, the steps described above may be implemented.

Wireless cells may be configured to work in either a static or dynamicmode as depicted in FIG. 62. In the static mode, a wireless cell may bemanually configured and/or load a stored configuration. The static modefunction may not allow the wireless cell to change channels orconfiguration to adapt to changes in clients, environment, or throughputspecifications. A wireless cell in the static mode includes similarcapabilities as a current 802.11 access point. In one embodiment, thestatic mode loads a stored configuration, sets the channels according tothe configuration, then enters the background loop. In the dynamic mode,in one embodiment, the wireless cell performs an active scan todetermine which channels will provide the best performance, loading, ordata throughput. After the active scan, the wireless cell checks foradvanced clients. If advanced clients are not found, the wireless celldetermines the optional channel for each radio, sets the channel foreach radio then enters the background loop. If advanced clients arepresent, the radio channels are set using the data gathered during theactive scan. The advanced clients may communicate with the wireless celland request a channel change if the assigned channel does not providethe throughput the client desires.

The background loop includes the functions which the wireless cellcontinuously performs or the conditions continuously checked. A possiblebackground loop is shown in FIG. 63. Similar to the power oninitialization, the background loop may operate in either a static ordynamic mode. In the static mode, a wireless cell includes similarcapabilities as a current 802.11 access point. In the static mode, thewireless cell may continuously perform the housekeeping functions toservice simple clients. In the dynamic mode, the wireless cell mayperform passive scans to check for new clients or other wireless cells.All new clients are added and serviced. Detection of a new wireless cellmay cause the background loop to assess the impact the new cell has onthe radio channels in current use. If the channel used by the newlydiscovered foreign wireless cell collides with the current channels inuse, the background loop may reassess which channels are best. If achange in channels is needed, the appropriate radios may be set to a newchannel. If a new configuration is not needed, or will not providebetter performance, balance, or throughput, no change may beimplemented.

As described above, advanced clients are capable of communicating withthe wireless cell. The diagrams shown in FIG. 64 through FIG. 68 showsome of the types of messages that may be sent between an advancedclient and the wireless cell. Each figure shows the communicationsbetween Client X, the Wireless Cell, and Other Client. Other Client mayrepresent one or more clients. In one embodiment, when Client Xdiscovers it is not receiving the throughput to operate, as shown inFIG. 64, it sends a request to the Wireless Cell to get a channel thatmay be capable of delivering the throughput. The Wireless Cell receivesthe optimization request message, and uses the data collected duringeither a passive or active scan to determine if there is a channel thathas less loading or interference that may possibly deliver greaterthroughput to Client X. If a channel is found, a channel change messageis sent to all clients. Client X and all Other Clients receive thechannel change message, change to their newly assigned channels, thendetermine if the new channel provides the throughput for operation.

After Client X switches to a new channel and the channel provides thedesired throughput, as shown in FIG. 65, Client X sends a message to theWireless Cell that the channel change was successful. The Wireless Cellterminates the throughput optimization process and sends a message toeach client that the channel change sequence is done. If the new channelassigned to Client X does not provide the desired throughput, as shownin FIG. 66, Client X sends a channel change unsuccessful message to theWireless Cell. When the Wireless Cell receives the message, itdetermines the next best channel assignment to enable Client X toreceive the desired throughput. The Wireless Cell sends new channelassignments to all clients. Each client sets the new radio channel, andthen determines if the new channel provides the necessary throughput.

If the throughput of one of the Other Clients is impaired by the newchannel assignment, as depicted in FIG. 67, the Other Client sends thechannel change unsuccessful message to the Wireless Cell. The WirelessCell determines the next best channel assignment and sends the newchannel assignments to each client. Each client changes to the newchannel, and then determines if the new channel provides the throughputnecessary for proper operation. At some point, the channel assigned toClient X may still not deliver the throughput desired for properoperation, yet the Wireless Cell may have exhausted all or mostavailable channel assignments. As shown in FIG. 68, when Client Xcommunicates to the Wireless Cell that the new channel assignment isunsuccessful because it does not deliver the desired throughput, theWireless Cell, in one embodiment, selects the best channel assignmentavailable, sends the channel assignment to the clients, and informs eachclient that no channel may provide the necessary throughput. At thatpoint, Client X may implement steps to resolve the problem. Some of theoptions for Client X may include, for example, at least one oftranscoding to a lower bit rate, displaying a message to the user,prioritizing desired throughput for multiple clients, redistributingclient load among available radios and/or antennas, or continuing tooperate with degraded performance.

Although the description above contains many details, these should notbe construed as limiting the scope of the invention but as merelyproviding illustrations of some of the exemplary embodiments of thisinvention. Therefore, it will be appreciated that the scope of thepresent invention fully encompasses other embodiments which may becomeobvious to those skilled in the art, and that the scope of the presentinvention is accordingly to be limited by nothing other than theappended claims, in which reference to an element in the singular is notintended to mean “one and only one” unless explicitly so stated, butrather “one or more.” All structural, chemical, and functionalequivalents to the elements of the above-described exemplary embodimentsthat are known to those of ordinary skill in the art are expresslyincorporated herein by reference and are intended to be encompassed bythe present claims. Moreover, it is not necessary for a device or methodto address each and every problem sought to be solved by the presentinvention, for it to be encompassed by the present claims. Furthermore,no element, component, or method step in the present disclosure isintended to be dedicated to the public regardless of whether theelement, component, or method step is explicitly recited in the claims.No claim element herein is to be construed under the provisions of 35U.S.C. 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for.” As used herein, the terms “comprises”,“comprising”, or any other variation thereof, are intended to cover anon-exclusive inclusion, such that a process, method, article, orapparatus that comprises a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus. Further, no elementdescribed herein is required for the practice of the invention unlessexpressly described as “essential” or “critical”.

1. A wireless cell that provides a virtual sector for simultaneouscommunication with a provided first wireless client and a providedsecond wireless client, the wireless cell comprising: a firstdirectional antenna having a first physical sector; a second directionalantenna having a second physical sector; a first radio couples to thefirst antenna; a second radio couples to the second antenna; and aprocessor couples to the first radio and the second radio; wherein: thefirst physical sector comprises an angle of coverage less than about 270degrees; the second physical sector comprises an angle of coverage lessthan about 270 degrees; the first physical sector overlaps at least 30percent of the second physical sector thereby forming the virtualsector; the first antenna and the second antenna are assigned a firstchannel and a second channel respectively responsive to a signal qualityscan of at least one of the first channel and the second channel usingat least one of the first antenna and the second antenna; the firstchannel and the second channel comprise different channels; the firstclient and the second client are positioned inside the virtual sector;and the first antenna and the second antenna simultaneously communicatewith the first client and the second client respectively.
 2. Thewireless cell of claim 1 wherein simultaneously communicate comprisestransmitting a radio signal.
 3. The wireless cell of claim 1 wherein thefirst client communicates with the second client.
 4. The wireless cellof claim 1 wherein the first antenna and the second antenna communicatea first data and a second data respectively.
 5. The wireless cell ofclaim 1 wherein at least one of the first antenna and the second antennacomprises a MIMO antenna.
 6. The wireless cell of claim 1 wherein thewireless cell communicates using at least one of an 802.11a, an 802.11b,an 802.11g, an 802.15, an 802.16, a Bluetooth, and an ultra-widebandcommunication protocol.
 7. A wireless cell that provides a plurality ofvirtual sectors for simultaneous communication with a provided firstwireless client and a provided second wireless client, the wireless cellcomprising: six directional antennas, each one antenna having a physicalsector, each physical sector having a first portion, a second portion,and an angle of coverage less than about 270 degrees, wherein: the firstportion and the second portion of each physical sector comprise at least30 percent of each respective physical sector and do not overlap; thefirst portion and the second portion of a first antenna of the sixantennas overlap the second portion of a fifth antenna of the sixantennas and the first portion of a sixth antenna of the six antennasrespectively, thereby respectively forming a first and a second virtualsector of the plurality of virtual sectors; the first portion and thesecond portions of a second antenna of the six antennas overlap thesecond portion of the sixth antenna and the first portion of a fourthantenna of the six antennas respectively, thereby respectively forming athird and a fourth virtual sector of the plurality of virtual sectors;the first portion and the second portions of a third antenna of the sixantennas overlap the second portion of the fourth antenna and the firstportion of the fifth antenna respectively, thereby respectively forminga fifth and a sixth virtual sector of the plurality of virtual sectors;the first antenna and the fourth antenna are assigned a first channel,the second antenna and the fifth antenna are assigned a second channel,and the third antenna and the sixth antenna are assigned a third channelresponsive to a signal quality scan of at least one of the firstchannel, the second, and the third channel using at least one of thefirst, second, third, fourth, fifth, and sixth antennas; the first, thesecond, and the third channels comprise different channels; the firstclient and the second client are positioned inside a one virtual sectorof the first through sixth virtual sectors; and a first antenna and asecond antenna of the six directional antennas that form the one virtualsector simultaneously communicate with the first client and the secondclient respectively.
 8. The wireless cell of claim 7 whereinsimultaneously communicate comprises transmitting a radio signal.
 9. Thewireless cell of claim 7 wherein the first client communicates with thesecond client.
 10. The wireless cell of claim 7 further comprising afirst, a second, and a third RF switch, wherein: the first RF switchcouples to the first and the fourth antennas; the second RF switchcouples to the second and the fifth antennas; and the third RF switchcouples to the third and the sixth antennas.
 11. The wireless cell ofclaim 10 further comprising three radios, wherein each one radio couplesto one respective RF switch.
 12. The wireless cell of claim 7 furthercomprising six radios, wherein each one radio couples to one respectiveantenna.
 13. The wireless cell of claim 11 further comprising aprocessor that sends data to and receives data from the radios.
 14. Thewireless cell of claim 12 further comprising a processor that sends adata to and receives data from the radios.
 15. The wireless cell ofclaim 7 wherein at least one of the six directional antennas comprises aMIMO antenna.
 16. The wireless cell of claim 7 wherein the wireless cellcommunicates using at least one of an 802.11a, an 802.11b, an 802.11g,an 802.15, an 802.16, a Bluetooth, and an ultra-wideband communicationprotocol.
 17. A first wireless cell that provides at least one virtualsector for simultaneous communication with a provided first wirelessclient and a provided second wireless client, the first wireless cellcomprising: at least two directional antennas, each one antenna having arespective physical sector, each one physical sector having an angle ofcoverage of less than about 270 degrees; at least two radios, each oneradio couples to at least one directional antenna; and a processor thatcouples to each radio; wherein: the antennas are positioned in such away that the physical sector of at least one of the antennas of thefirst wireless cell overlaps the physical sector of at least one of theother antennas of the first wireless cell by at least 30 percent therebyforming a respective virtual sector of the at least one virtual sector;the antennas whose physical sectors overlap are assigned differentchannels of a plurality of channels responsive to a signal quality scanof at least two of the plurality of channels using at least one of theantennas; the first client and the second client are positioned inside aone virtual sector of the at least one virtual sector; and a firstantenna and a second antenna of the at least two directional antennasthat form the one virtual sector simultaneously communicate with thefirst client and the second client respectively.
 18. The first wirelesscell of claim 17 wherein simultaneously communicate comprisestransmitting a radio signal.
 19. The first wireless cell of claim 17wherein the first client communicates with the second client.
 20. Thefirst wireless cell of claim 17 wherein the first antenna and the secondantenna communicate a first data and a second data respectively.
 21. Thefirst wireless cell of claim 17 further comprising: at least two RFswitches and at least four directional antennas, wherein: each one RFswitch couples in series between one of the at least two radios and atleast two of the at least four antennas respectively.
 22. The firstwireless cell of claim 17 further comprising at least two attenuators,wherein: each one attenuator couples in series between one radio and atleast one antenna; and each one attenuator attenuates at least one of anincoming signal and an outgoing signal.
 23. The first wireless cell ofclaim 17 wherein the processor sends data to and receives data from theat least two radios.
 24. The first wireless cell of claim 17 wherein theprocessor sends control information to and receives control informationfrom the at least two radios.
 25. The first wireless cell of claim 22wherein the processor controls an aMount of attenuation of at least oneof the at least two attenuators.
 26. The first wireless cell of claim 17wherein at least one of the at least two directional antennas comprisesa MIMO antenna.
 27. The first wireless cell of claim 17 wherein thefirst wireless cell communicates using at least one ofan 802.11a, an802.11b, an 802.11g, an 802.15, an 802.16, a Bluetooth, and anultra-wideband communication protocol.
 28. The first wireless cell ofclaim 17 wherein a combined area of coverage of the physical sectors ofthe at least two directional antennas is about 360 degrees.